﻿Molecular and morphological identification of larvae of Carangidae (Teleostei, Carangiformes) species from southern Gulf of California

﻿Abstract The description of diagnostic morphological characters and DNA barcoding of fish larvae from nine species of the carangid family are provided from specimens collected during a weekly zooplankton time-series (2016–2017) at Cabo Pulmo National Park, Gulf of California, Mexico. Five nominal species (Caranxsexfasciatus, C.caballus, Naucratesductor, Selarcrumenophthalmus, and Seleneperuviana) and three morphotypes of Decapterus spp. and one of Caranx spp. were identified and separated based on morphological, meristic, and pigmentary diagnostic characters. All larvae were genetically sequenced for a fragment of the cytochrome c oxidase subunit I mitochondrial gene. Sequences of larval Caranx and Decapterus showed high genetic similarity (> 99%), low intraspecific divergence (< 1%), and an interspecific divergence between 6% and 11%, allowing the discrimination of diagnostic pigmentation patterns of fish larvae among three sibling species from each genus: Caranx (C.caballus, C.caninus, and C.sexfasciatus) and Decapterus (D.macarellus, D.macrosoma, and D.muroadsi). DNA barcoding supported the presence of Caranxcaballus, C.caninus, C.sexfasciatus, Decapterusmacarellus, D.muroadsi, Selarcrumenophthalmus, and Seleneperuviana, and for the first time Naucratesductor and D.macrosoma at the CPNP. Abundance of these nine species (confirmed molecularly) was estimated throughout the 2016–2017 weekly time series. Decapterusmacarellus and Caranxcaninus were the most abundant species. The morphological and molecular taxonomic methods allowed us to infer the species number and abundance of these commercial species at the CPNP to improve conservation in protected areas and fishery management.


Introduction
Rapid, cost-effective, and precise identification of species of fish larvae facilitates better resolution to the analysis of ichthyoplankton communities (diversity, abundance, and distribution patterns).Despite the monumental taxonomic effort of fish larval description keys for fish species identification in the Eastern Pacific and other regions of the world (Moser 1996;Watson et al. 1996;Beltrán-León and Ríos-Herrera 2000;Richards 2005), there is still a high percentage of species without available ontogenetic larval descriptions relative to the fish diversity for the Mexican Pacific and Gulf of California (Kendall and Matarese 1994).The family Carangidae is highly diverse and includes several species that are targets of relevant artisanal fisheries that provide socio-economical resources to local people.At least 33 nominal species of Carangidae have been reported in the Eastern Pacific based on juvenile and adult specimens (Smith-Vaniz 1995).From them, only 18 species have had their larval stages described (Watson et al. 1996;Beltrán-León and Ríos-Herrera 2000).This taxonomic information has allowed the publication of several ichthyoplankton checklists from different regions of the Mexican Pacific, including the Gulf of California.However, several taxa from this region have frequently been identified only to the genus level (i.e., Caranx spp., Decapterus spp., Oligoplites spp., Selene spp., and Seriola spp.; Aceves-Medina et al. 2003;González-Armas et al. 2008;Silva-Segundo et al. 2008;Avendaño-Ibarra et al. 2014).
Five nominal species of Caranx genus have been reported in the Mexican Pacific, including the Gulf of California: Caranx sexfasciatus Quoy & Gaimard, 1825; Caranx melampygus Cuvier, 1833; Caranx lugubris Poey, 1860; Caranx caninus Günther, 1867; and Caranx caballus Günther, 1868 (Smith-Vaniz 1995;Allen and Robertson 1998;Froese and Pauly 2000).Sumida et al. (1985) reported morphological and meristic descriptions of fish larvae of Caranx caballus and Caranx sexfasciatus.Those larval descriptions were later evaluated using molecular DNA barcoding methods that concluded that the main diagnostic morphological characters originally assigned to C. sexfasciatus were larvae of C. caninus, while C. caballus was corroborated with the original morphological description (Silva-Segundo et al. 2021).In addition, Ahern et al. (2018) reported fish eggs and larvae of Caranx caninus and C. sexfasciatus based on molecular methods (COI), but without formal morphological analysis of specimens collected in Cabo Pulmo National Park (CPNP).The current study involved an integrative (molecular and morphological) approach to distinguishing between the several larval morphotypes of Caranx species.
Juveniles and adults of three nominal species of the genus Decapterus have been reported in the Mexican Pacific and the Gulf of California (Smith-Vaniz 1995): Decapterus macarellus Cuvier, 1833; Decapterus macrosoma Bleeker, 1851; and Decapterus muroadsi Temminck & Schlegel, 1844.However, there is currently only a morphological description of the larval development of D. macarellus from specimens collected in the western central North Atlantic (Laroche et al. 2005), and D. muroadsi (only in postflexion stage) from specimens collected in the Colombian Pacific (Beltrán-León and Ríos-Herrera 2000).Ahern et al. (2018) identified eggs and fish larvae using molecular methods (COI) of D. macarellus and D. muroadsi.However, both species lack formal morphological description to morphologically identify the larvae.Fish larvae of the genera Oligoplites, Selene, and Seriola also currently lack a proper morphological description matched with DNA corroboration.
The present study uses DNA barcoding to obtain a higher resolution and precision in the identification of several fish larval morphotype sibling species of the genera Caranx and Decapterus (Family Carangidae) not adequately or not described yet.Once the taxonomic identity was confirmed molecularly, key diagnostic characters will be chosen to discriminate Caranx and Decapterus larvae at the species level from specimens collected in the southwest region of the Gulf of California.Taxonomic investigation of carangid fish larvae is a requirement for delimitating distribution patterns, spawning periods, larval drift and the species compositions of communities.All this information is helpful for the adequate management of species of commercial and ecological importance, especially in regional artisanal fisheries surrounded by the protected no-take area of Cabo Pulmo National Park.

Field work and morphological comparisons
Analyzed fish larvae were collected from a weekly zooplankton time series conducted between January 2016 and November 2017 at Los Morros (23°27′N, 109°25′W), at Cabo Pulmo National Park (CPNP), the closest coral reef to the town of Cabo Pulmo (Fig. 1A, B).Zooplankton samples were collected aboard small boats, regionally known as "pangas" (5.8-8.5 m in length powered by a 200 hp outboard motor), using a standard conical net with 300 μm mesh net (0.60 m mouth diameter and 2.1 m length).The zooplankton net was towed with a rope from the "panga" stern for 10 min near the sea surface (≤ 5 m depth) with the boat angled slightly so that the tow path followed a wide arc that kept the net clear of the turbulence caused by the engine.The seafloor depth at the Los Morros site ranges between 20 and 30 m.The zooplankton net was equipped with a calibrated General Oceanics digital flowmeter (model 2030R) to estimate the filtered seawater volume to calculate the standardized abundance of fish larvae (ind.1000 m -3 ; Smith and Richardson 1977).Zooplankton samples were passed through a 300-μm sieve on board to remove the seawater and zooplankton was preserved in 96% non-denatured ethanol, with a complete change of ethanol after 24 h for molecular analysis.
All carangid larvae were sorted from the zooplankton samples (without aliquots) and identified to the most precise taxonomic level using meristic and pigmentation characters, based on previous larval descriptions (Sumida et al. 1985;Watson et al. 1996;Beltrán-León and Ríos-Herrera 2000;Laroche et al. 2005).Several specimens were deposited in the reference collection of the Centro Interdisciplinario de Ciencias Marinas del Instituto Politécnico Nacional, La Paz, BCS, Mexico (CICIMAR-IPN).Carangid larval stages representing all collected morphotypes were selected for further DNA extraction.The total length of each larva was measured with a calibrated micrometer and photographed using a digital camera attached to a stereoscope.Digital photographs were used to draw detailed comparative schematics of the stages obtained for larvae of different total lengths.
We used the basic local alignment search tool (BLAST) included in GENE-IOUS® software.COI sequences from our study were compared with COI sequences (mostly from adult specimens) previously deposited in the System of Barcode of Life Data Systems (BOLD Systems) and National Center for Biotechnology Information (NCBI) databases.We downloaded 179 COI sequences published of adult specimens of the same lengths as available nominal species of Carangidae in NCBI and BOLD Systems databases to facilitate sequence comparison (Suppl.material 1: table S1).We used DnaSP software to obtain the number of haplotypes for each species to remove redundancy in the entire sequence dataset (Rozas et al. 2003).The sequence of the common dolphinfish Coryphaena hippurus Linnaeus, 1758 (Coryphaenidae) downloaded from Gen-Bank accession number MH638665 (Xu et al. 2019) was used as a cluster tree outgroup due to its close relation with the Carangidae (Smith-Vaniz 1984;Reed et al. 2002;Damerau et al. 2018).All COI sequences were aligned (ClustalW), using MEGA 10.0.5 software to calculate the intra-and inter-specific pairwise genetic distances of COI gene sequences using the Kimura 2-parameter model (K2P) and Neighbor-Joining tree reconstruction (NJ) with 10,000 bootstraps following standard methods (Kumar et al. 2016).The analysis was repeated with best-fit model and Maximum Likelihood (ML) with similar results.Any way, we decided to use the NJ and K2P methods by comparative propose with previous published articles on fish (e. g. Ward et al. 2005).Once the species were molecularly identified, the species number and abundance (ind.1000 m -3 ) were plotted for the 2016-2017 zooplankton time series.
A total of 57 COI sequences from the present study and 179 sequences downloaded from GenBank and BoldSystems were aligned.From this database, the representative haplotypes for each species were obtained (Suppl.material 1: table S1).These haplotypes were used for the analysis of genetic distances and the reconstruction of the Neighbor-Joining tree (NJ).Intraspecific genetic distances (K2P model) ranged between 0.20% and 1.34% and interspecific differences of species of the same genus varied between 8.4% and 11.7% among Caranx and between 6.4% and 6.5% among Decapterus species.The distances between genera showed values between 14.2% and 22.8% (Suppl.material 1: table S2).The reconstruction of the NJ tree showed five main clusters corresponding to the five genera found in the present study (Caranx, Decapterus, Naucrates, Selar, and Selene).The clusters of the genera Caranx and Decapterus showed three subgroups corresponding to their respective species (C.caballus, C. caninus, and C. sexfasciatus; D. macarellus, D. macrosoma, and D. muroadsi; Fig. 2).All the COI sequences of the present study were grouped in their representative clusters (comparing with adults of each species), corroborating the specific identification of the larvae collected in CPNP during 2016-2017 (Fig. 2).The morphological characteristics of Naucrates ductor, Selar crumenophthalmus, and Selene peruviana larvae identified in the present work were not described here because complete morphological descriptions of their larval development are already available in Watson et al. (1996).However, it was necessary to provide detailed descriptions of pigmentation patterns and diagnostic characters of fish larvae of the genera Caranx and Decapterus because there is little information on the first larval stages of these two genera.Here we describe the diagnostic characters that allow species distinction among Caranx larvae (Caranx caballus, C. caninus, and C. sexfasciatus) and among Decapterus larvae (Decapterus macarellus, D. macrosoma, and D. muroadsi).When it was not possible to count fin rays and spines, information from the taxonomic guides for each species was used.Preflexion larvae 2.5 mm total length.(Fig. 3A) Body slender, second spine at preopercular angle large.Pigmentation: lower jaw with pigment; upper edge of gut; small dorsal pigment between third and fifth myomeres, large pigments between 9-12 myomeres; in lateral midline between myomeres 12-15; ventrally, one posterior to cleithral symphysis, central portion of gut, one close to anus, and postanal series from the second postanal myomere to notochord.Pattern of pigments present in larvae <3.7 mm.

Diagnostic characters of larvae of Carangidae
Preflexion larvae 3.2 mm.(Fig. 3B) Deeper body with broad crest from parietal to supraoccipital region, which is not high.Two robust preopercular spines at preopercular angle.Pigmentation: Three pigments on parietal and supraoccipital region; internal pigment on brain and upper margin of gut (swim bladder and terminal section).
Flexion larvae 3.7 mm.(Fig. 3C) Slightly higher supraoccipital crest and one pair of pterotic and supracleithral spines.Preopercular spines long and robust at the base; thin at ends.Pigmentation: Pigments scattered over lower jaw tip and chin; over head, from eye (upper edge) to supraoccipital region; ventrally, between lower jaw angle and cleithra; upper margin of gut completely pigmented, like ventral margin and central part (lateral view); on trunk, dispersed from dorsal pteryogyophores to lateral midline, with internal pigments between lateral midline and dorsum.Pattern consistently matches original larvae of Caranx caballus (Sumida et al. 1985).
Preflexion larvae 2.5 mm total length.(Fig. 4A) Small supraocular crest, five spines on preopercular edge (third and fourth longer and more robust than others).Pigmentation: Pigments on tip of lower jaw; mandibular angle and branchiostegal membrane; intensified on upper margin of gut over swim bladder, several on ventral margin of gut coil, one on terminal section anterior to anus, heavier and extended in larger sizes.Dorsal and ventral pigment series between myomeres 12-15, followed by small pigments until notochordal tip, three of which appear on lower lobe of caudal fin primordium.
Preflexion larvae 3.2 mm.(Fig. 4B) Head slightly deeper, with supraoccipital crest short and slightly raised base, preopercular spines more elongated and supraocular ridge with crescent tip.Pigmentation: Pigments above head, on midbrain; dorsal and ventral dispersed between myomeres 12-17; on upper edge of gut sparse, but heavy on dorsal swim bladder.Preflexion larvae 3.4 mm.(Fig. 4C) Head and trunk deeper, supraocular ridge larger with pronounced tip, preopercular spines thin, elongated and more pronounced in angle.Pigmentation: Pigments increasing on head compared to smaller sizes; supraoccipital crest pigmented; on chin; in branchiostegal membrane and rays; on upper edge of gut disperse, but heavy and intense on lower margin, marked at level of anus; on trunk (dorsally); above lateral midline (myomeres 3-5), and another series in myomeres 13-18 strongly pigmented and widespread from dorsal to anal pterygiophores; and ventral series of small pigments in caudal region, one on lower lobe of caudal fin fold, and three at lower margin of notochordal tip.
Flexion larvae 4.1 mm.(Fig. 4D) Deeper body compared with smaller sizes, with supraoccipital crest extended between frontal to occipital area, with serrated edge.Supraocular crest comparatively high tip, and preopercular spines thinner and elongated, mainly in the preopercular angle.Pigmentation: More pigments in jaws; on branchiostegal rays; over brain and crest; in upper and ventral gut margin, and in most of trunk (including some on lateral midline); except in central (myomeres 9-12) and caudal region without pigmentation.
Main characters.Pigmentation on dorsal and ventral series between myomeres 12-15; gut, several on ventral margin of gut coil, one on terminal gut section anterior to anus; and pigmented supraoccipital crest in larvae > 3.4 mm.
Preflexion larvae 2.8 mm total length.(Fig. 5A) Slender trunk, slightly deep head, supraoccipital crest with short base and without pigmentation, well-developed preopercular edge spines, mainly angle spine.Pigmentation: Scarce on almost entire body; present in mandibular angle; internal in upper margin of gut and some on swim bladder; no pigmentation ventrally; and few posteriors to cleithral symphysis.On trunk, several on dorsal edge between 11-17 myomeres and small pigments in lateral midline; and postanal to end of notochord.
Preflexion larvae 3.5 mm.(Fig. 5C) Deeper head and trunk, with broad-based supraoccipital crest; and longer and thinner spines in preopercular margin.Pigmentation: Denser than in smaller sizes; supraoccipital crest not pigmented; on head, at forebrain and nape; marked in tip of jaws; over lower angle of jaw; and lower margin of preopercular spines and branchiostegal membrane; on trunk, internally over first seven myomeres and lateral midline.
Main characters.Less pigmented larvae compared with C. caninus and C. caballus.Dorsal series of pigments between 11-17 myomeres and in lateral midline.Scarce ventral pigmentation on gut and no pigmentation on supraoccipital crest, in all sizes.
Preflexion larvae 2.2 mm total length.(Fig. 6A) Slender and elongated body, with short and thinner preopercular spines.Pigmentation: On jaws tip; cleithral symphysis; below pectoral fin; on trunk, parallel series on dorsal and upper gut margin; on lateral midline a single pigment; on caudal zone, a series from last two myomeres to end of notochord, in all forms; and one above notochord tip.
Preflexion larvae 2.7-3.5 mm.(Fig. 6B, C) Elongated and deeper body.Pigmentation: Pattern like the smallest (2.2 mm), unlike one pigment in mandibular angle, on head, in section anterior and posterior to cleithral symphysis, and lateral midline intensifies.
Flexion larvae 4.2 mm.(Fig. 6D) Noticeably deeper body, with thin spines on preopercular edge, and one elongated at angle; with broad supraoccipital crest at its base, with low height and irregular serrated profile.Pigmentation: Denser on head; some on lower jaw profile; a series marked in dorsal margin; streaks on dorsum and ventrum extended on each side of dorsal an anal fins base; and scattered in the lower lobe of caudal finfold.Main characters.On trunk, parallel series of pigments marked on dorsal profile and on upper gut margin; and one pigment at lateral midline in small sizes; increased pigmentation with age.
Preflexion larvae 2-2.9 mm total length.(Fig. 7A, B) Slender and elongated bodies, slightly more robust in 2.9 mm; supracleithral crests with short base and lower height; with short preopercular spines and elongated one at angle.Pigmentation: On head just behind nape; chin; mandibular angle; above cleithral symphysis; at upper margin of opercular area; on gut and upper margin mainly over swim bladder and anterior margin of gut; on trunk, on upper margin between myomeres 7-9; postanal, just posterior to anus; three more on ventral margin of notochord tip.Flexion larvae 3.8 mm.(Fig. 7C) Slightly increase in body depth.Supraoccipital ridge base comparatively broad with slightly serrated margin, one pair of supracleithral spines, comparatively shorter preopercular spines than other species, robust base in angle.Pigmentation: On head, stronger over forebrain and nape and internally-placed posterior to eye; in lateral midline internal and contracted; on trunk, over dorsal and ventral margins; one at center of hypural plate.
Postflexion larvae 8.1 mm.(Fig. 7D) Elongated and slightly deep bodies.Supraoccipital and supraocular crests and supracleithral spines reduced, preopercular spines larger and more robust.Pigmentation: concentrated on head, internal pigments behind eye; on jaws tips and its lower margin; up to mandibular angle and around cleithral symphysis; on anterior and upper margin of gut; on trunk, dorsal series extended to myomere 20; over lateral midline and anal fin base; three stellate melanophores in hypural plate.
Main characters.Pigmentation behind the nape; on upper margin between myomeres 7-9; ventrally, one postanal just before anus and three more on notochord tip (< 3.8 mm).In postflexion stages, it extends in dorsal and ventrally margins, lateral line, and three stellate pigments in center of hypural plate.

Decapterus muroadsi Temminck & Schlegel, 1844
Material examined.One larva in preflexion identified as D. muroadsi.Myomeres 24 (10 precaudal and 14 caudal).Fins development not observed.Meristic data for D. muroadsi larvae have been reported by Watson et al. (1996): 10 precaudal Preflexion larvae 3.2 mm total length.(Fig. 8) Elongated body, with short preopercular spines.Pigmentation: Heavier on dorsal and ventral margin than other species of Decapterus; on head; in both jaws tips, mandibular angle and cleithral symphysis; upper margin of gut which merges with those of trunk; over gas bladder; and ventrally on gut and finfold near to anus; on trunk, in lateral midline (myomere 14); parallel from dorsal and ventrally profile; and around lower and upper lobes of caudal finfold.
Main characters.Preflexion larvae more pigmented than other Decapterus species, with line of pigments on dorsal and ventral margins along almost entire contour, ventrally pigmented in gut, and one anterior to anus over finfold.

Species abundance during 2016-2017 weekly time series
Larval Carangidae were collected during most of 2016, except in winter (December-February; Fig. 9).All species, except S. peruviana, were observed during 2016.The highest species number and abundance were observed during summer 2016 (July-September) with Decapterus macarellus being the most abundant in September (622 ind.1000m -3 ).During 2017, species number and abundance decreased and were recorded mostly during June-August (Caranx caballus, C. caninus, D. macrosoma, Naucrates ductor and Selene peruviana).Caranx caninus was the most abundant species (438 ind.1000 m -3 in July).Naucrates ductor and D. macrosoma are newly recorded species for the CPNP region, not previously reported in checklists in any life phase (egg, larvae, adult).The presence of larval stages of N. ductor and D. macrosoma larvae during both years suggest that both species are residents of the CPNP (Fig. 9).

Discussion
The present study provides the first morphological and molecular evidence to distinguish three sibling species of the genus Caranx, complementing molecular descriptions previously reported in Silva-Segundo et al. (2021).In addition, diagnostic characters to distinguish larvae of three species of Decapterus not previously described are provided.These descriptions rapidly and accurately delimit six fish larvae species without the need for molecular methods, facilitating future ecological research.
The juvenile and adult ichthyofauna at Cabo Pulmo National Park has been monitored since it was founded in 1995 as a no-take protected national park (Reyes-Bonilla 1997;Aburto-Oropeza et al. 2011, 2015;Olivier et al. 2022).
Currently, the reef ecosystem is healthy, with notable increases in the diversity, abundance, and biomass of fish species relative to 1995 (Alvarez-Filip et al. 2006;Alvarez-Filip and Reyes-Bonilla 2006;Saldívar-Lucio and Reyes-Bonilla 2011;Aburto-Oropeza et al. 2011, 2015;Ahern et al. 2018;Olivier et al. 2022).The fish taxonomic checklists of CPNP obtained from visual censuses of adult fish showed the presence of 14 species of carangids (Villarreal-Cavazos et al. 2000;Ayala-Bocos et al. 2018).Subsequently, based on molecular data from eggs and larvae, three more species of Carangidae were recorded in the CPNP (Ferdauia orthogrammus, Decapterus muroadsi, and Selene peruviana; Ahern et al. 2018).In the present study, D. macrosoma and Naucrates ductor are added to the checklist, recording a total of 19 species of Carangidae at the CPNP (Suppl.material 1: table S3).
Adults of five species of the Caranx genus have been recorded in the Mexican Pacific region: Caranx caninus, C. caballus, C. melampygus, C. lugubris, and C. sexfasciatus (Smith-Vaniz 1995;Allen and Robertson 1998;Froese and Pauly 2000).The larvae of C. caballus and C. sexfasciatus are the only species with larval descriptions (Sumida et al. 1985;Beltrán-León and Ríos-Herrera 2000).The larvae of C. caballus presented a pigmentation pattern and meristic elements like the original description by Sumida et al. (1985).However, in the present study, the larvae also have a small series of dorsal pigmentation that extends between the third and fifth myomeres in all sizes.
The larvae of Caranx sexfasciatus identified in Sumida et al. (1985), were larvae of C. caninus based on molecular evidence reported in Silva-Segundo et al. ( 2021), the latter species without formal description until the present study.The integration of morphological data and DNA barcoding of C. caninus and C. sexfasciatus has allowed us to detect the main diagnostic features separating both species larvae.The larvae of C. caninus have characteristic melanophores along the ventral margin of the gut, dorsal and ventral series of melanophores between myomeres 12-15 forming a vertical stripe-like which expand according to larval development, with melanophores on the head and supraoccipital crest since larvae of 3.4 mm.In contrast, the larvae of C. sexfasciatus showed little pigmentation in the cleithral symphysis region, few and small melanophores in the dorsal and ventral part, with a small pigment in the midline, in the middle of the body, which spreads as the larvae grow.In addition, the larvae have few pigments on the dorsal margin and some postanal pigments distributed to the end of the notochord.
Adults of Decapterus macarellus, D. macrosoma, and D. muroadsi were previously recorded in the Mexican Pacific (Smith-Vaniz 1995;Allen and Robertson 1998;Froese and Pauly 2000).According to Watson et al. (1996), Decapterus sp. could correspond to D. macrosoma based on the meristic information and pigmentation pattern, which was corroborated with larvae collected in the present study based on their high genetic similarity with sequences of adults of D. macrosoma.Although the larvae of D. macarellus had not been recorded in the Mexican Pacific, sequenced specimens of the species showed a similar pattern of pigmentation with larvae previously described by Laroche et al. (2005) in the Atlantic, confirming its circumglobal tropical distribution pattern.The preflexion larvae identified in the present study as D. muroadsi using DNA barcoding showed a pigmentation pattern considerably distinct from the larvae of D. macarellus and D. macrosoma, with melanophores along almost the entire dorsal and ventral profile of the trunk (Laroche et al. 2005).Our D. muroadsi larvae was like those reported by Steinke et al. (2016) from South Africa.Additionally, a similar pattern of pigmentation was observed in another postflexion larva (8.8 mm) collected in the Colombian Pacific (Beltrán-León and Ríos-Herrera et al. 2000).
The present study provides larval descriptions in different ontogenetic stages of comparative development among three species of Caranx (C.caballus, C. caninus, and C. sexfasciatus).However, it is necessary to mention that the larval stages of two other species present in the southern region of the Gulf of California (C.melampygus and C. lugubris) are still unknown and need to be morphologically and molecularly identified.Therefore, it is necessary to continue analyzing zooplankton samples and increase the taxonomic information of the group of carangid larvae.The combination of morphological and molecular taxonomic methods allowed us to find and distinguish pigmentation patterns that can be used as diagnostic features to separate commercially important fish species (Caranx and Decapterus).In addition, more precise information about species number and abundance of the larvae of carangid species from the Cabo Pulmo National Park is now available, which can be used for future management and conservation plans of these species that are an artisanal fishing resource outside the national park.

Figure 1 .
Figure 1.A Cabo Pulmo National Park (CPNP) (red outline) located in the southeast region of Baja California peninsula (inset) and B bathymetry of the national park measured with 120 kHz echosounder showing the locations of the weekly zooplankton time series (2016-2017; figure obtained from Ahern et al. 2018).

Figure 9 .
Figure 9. Larval abundance of the family Carangidae from Cabo Pulmo National Park, Mexico, surveyed weekly during 2016-2017.